1. Field of the Invention
The present invention relates to a hand-held drive-in tool for driving fastening elements in a constructional component or a workpiece and including a drive-in ram displaceably supported in a guide for driving fastening elements in the constructional component or the workpiece, a drive for driving the drive-in ram and having a driving spring member for displacing the drive-in ram, a device for preloading the driving spring member, a locking device having a locking position in which the locking device retains the driving spring member in its preloaded position and a release position into which the locking device is displaced upon actuation of an actuation switch of the drive-in tool.
2. Description of the Prior Art
The advantage of drive-in tools of the type described above consists in using a low-cost mechanical driving spring member, which permits to economically manufacture this type of drive-in tools.
A drive-in tool of the type described above is disclosed in U.S. Pat. No. 3,847,322. In the disclosed drive-in tool, a drive-in ram is preloaded against a driving spring member by a motor-driven preloading mechanism. A locking device retains the drive-in ram and the driving spring member in the preloaded position. To this end, the locking device has a locking member that lockingly engages a locking surface on the drive-in ram. The locking device is released by an actuation switch, whereby the locking device is lifted off its locking position by a motor-driven mechanism and is displaced in a release position. In the release position of the locking device, the drive-in ram is displaced in the setting direction by the biasing force of the driving spring member for driving a fastening element in a workpiece.
The drawback of the known drive-in tool consists in that at an inadvertent acceleration of the drive-in tool, e.g., when it falls from an elevated position to a relatively low position, the locking device can inadvertently be displaced into its release position.
Accordingly, an object of the present invention is a drive-in tool in which the above-discussed drawback a known drive-in tool is eliminated.